Technical Field
The present disclosure relates to a light-emitting device.
Discussion of the Background
Various Chip-on-Board (COB) light-emitting devices each including a plurality of light-emitting elements on its board are being developed in recent years (for example, Japanese Unexamined Patent Application Publication No. 2013-69824). In the COB light-emitting devices, wiring is disposed on the boards and electrically connected to the light-emitting elements. Also, disposing a plurality of light-emitting elements on the board enables the COB light-emitting device to provide a high light output.
In COB light-emitting devices as disclosed in Japanese Unexamined Patent Application Publication No. 2013-69824, to obtain an even higher output, it is necessary that light-emitting elements are arranged at narrow pitches or that sufficient creepage distances be secured when a plurality of light-emitting devices are used in a parallel arrangement. Thus, it is difficult to secure areas for wiring on boards when the light-emitting elements are disposed to the edges of the boards. To address the difficulty, it is conceivable to use multi-layer wiring boards as mounting boards, for example. Use of the multi-layer wiring boards, however, worsens the heat dissipation performance because insulating materials having comparatively low thermal conductivities are used between the layers of the multi-layer wiring. Accordingly, the multi-layer wiring boards are unsuitable for the COB light-emitting devices in which a plurality of light-emitting elements generate a large amount of heat.
An embodiment according to the present disclosure has an object to provide a light-emitting device in which a plurality of light-emitting elements can be disposed densely.